1. Field of the Invention
The present invention relates to an AM data multiplexing modulation apparatus for multiplexing a digital signal to an AM modulation signal and transmitting it.
2. Description of the Related Art
A conventional data multiplexing system is broadly classified into a time division multiplex system used for character multiplex broadcasting of TV broadcasting and a frequency division multiplex system used for character multiplex broadcasting of FM broadcasting. AM broadcasting has a narrow occupied bandwidth and cannot be used for frequency division multiplex and time division multiplex. AM data multiplexing modulation apparatus for multiplexing a digital signal to an AM modulation signal is not used as yet, although data multiplex broadcasting such as TV broadcast and FM broadcast are presently used.